IIRC, Tim has very limited access to some of the crazier bobbin colours, aside from white, black, creme, and apparently purple being a newer one. To make a pickup using a different colour, BK has to make about 100 bobbins. So, unless they feel that the colour you've chosen will be put into 99 more pickups, it will not be made.
Don't give up hope, tho -- there is another solution!
You can buy a pup from another manufacturer and have BK 'rewind' the pup (basically, it will be rebuilt around your bobbins) with the colours of your choice.
I am having a Cold Sweat made out of a black/yellow zebra Seymour Duncan pup. (Not in the immediate future, as the cost of buying a new Duncan and the cost of a BK here in the US is a bit much for a single humbucker at the moment; by the end of the year I hope to have this on order, tho)